Put live register bits in stackmaps.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index d6da85389a64bce8e35f1580641c431ab776d3f1..9cb04ff5b87e8d19a365c44b89de7259ccb3787c 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -6789,7 +6789,9 @@ void Stackmap::SetBit(intptr_t bit_index, bool value) const {
 }
 
 
-RawStackmap* Stackmap::New(intptr_t pc_offset, BitmapBuilder* bmap) {
+RawStackmap* Stackmap::New(intptr_t pc_offset,
+                           BitmapBuilder* bmap,
+                           intptr_t register_bit_count) {
   ASSERT(Object::stackmap_class() != Class::null());
   ASSERT(bmap != NULL);
   Stackmap& result = Stackmap::Handle();
@@ -6822,6 +6824,7 @@ RawStackmap* Stackmap::New(intptr_t pc_offset, BitmapBuilder* bmap) {
   for (intptr_t i = 0; i < length; ++i) {
     result.SetBit(i, bmap->Get(i));
   }
+  result.SetRegisterBitCount(register_bit_count);
   return result.raw();
 }